Steel slag handling system and method for using

ABSTRACT

A system is described for improved processing and disposal of molten steel slag formed during steel furnace operation. The system comprises steel slag granulator apparatus of the type described in detail in copending U.S. Pat. application Ser. No. 428,519 and associated equipment including controllable molten slag feeding apparatus, aspirator-pump means for collecting the steam generated during the slag granulation process, and for transferring it to a suitable disposal point, an improved water nozzle arrangement to produce a U-shaped or H-shaped jetstream of water for slag granulation, and a hydraulic transport apparatus for conveying the granulated and cooled steel slag away from the granulator in the form of a water-slag slurry. The system also includes slag dewatering apparatus to extract the granulated slag particles from the slurry to permit storage or disposal in relatively dry form, and high-efficiency filtering means to permit direct disposal of the granulating water in nearby rivers or sewers without danger of contamination due to high solids concentration in the discharged water. One embodiment includes means for stockpiling the dried slag directly on the ground, while a second embodiment includes means for classifying the slag particles by size prior to storage.

tates Patent Grady, deceased n51 3,645,78 [4 1 *Feb. 29, E972 [54] STEELSLAG HANDLING SYSTEM AND METHOD FOR USING John J. Grady, d m late of NewFlorence, Pa. by Betty Jane Grady, executrix International SteelWashington, DC.

The portion of the term of this patent subsequent to Apr. 25, 1984, hasbeen disclaimed.

Filed: Dec. 4, 1969 Appl. No.: 882,317

Related US. Application Data Continuation of Ser. No. 632,704, Apr. 21,1967, abandoned, and a continuation-in-part of Ser. No.

[72] Inventor:

[73] Assignee:

Slag Corporation,

Notice:

632,822, Apr. 21, 1967, Pat. No. 3,523,015, and Ser.v No 63 2 l04, and Se r. No. 632,822, Confirmation-in part of Ser. No. 428,519, Jan. 27,1965, Pat. No. 3,316,075, and a continuation-in-part of 535,143, Mar.17, 1966, abandoned, and Ser. No. 428,519, and Ser. No. 535,143,Continuation-impart of Ser. No. 126,792, June 21, 1961, abandoned.

Field of Search ..65/ 19, 20, 141; 75/24 ll eferences cited 1 v 7 UNITEDSTATES PATENTS mom wmn sum Primary Examiner-Arthur D. AssistantExaminerRobert L AtlorneyLeBlanc & Shur Kellogg Lindsay A system isdescribed for improved processing and disposal of molten steel slagformed during steel furnace operation. The system comprises steel slaggranulator apparatus of the type described in detail in copending US.Pat. application Ser. No. 428,519 and associated equipment includingcontrollable molten slag feeding apparatus, aspirator-pump means forcollecting the steam generated during the slag granulation process, andfor transferring it to a suitable disposal point, an improved waternozzle arrangement to produce a U-shaped or l-l-shaped jetstream ofwater for slag granulation, and a hydraulic transport apparatus forconveying the granulated and cooled steel slag away from the granulatorin the form of a water-slag slurry. The system also includes slagdewatering apparatus to extract the granulated slag particles from theslurry to permit storage or disposal in relatively dry form, andhighefficiency filtering means to permit direct disposal of thegranulating water in nearby rivers or sewers without danger ofcontamination due to high solids concentration in the discharged water.One embodiment includes means for stockpiling the dried slag directly onthe ground, while a second embodiment includes means for classifying theslag particles by size prior to storage.

27 Claims, 8 Drawing Figures 8/1970 Grady ..65/l9 PATENTEDFEBZS m2 SHEET1 OF 3 .W\ .........HH. n I v@ QQ $9 m3 vQ wQ QQ m @mm 8 E S:

bmaDm mp5; 20mm INVEN'IOR JOHN J. GRADY ATTORNEYS STEEL SLAG HANDLTNGSYSTEM AND METHOD FOR USING lNTRODUCTlON This application is acontinuation of copending application, Ser. No. 632,704, filed Apr. 21,1967 now abandoned entitled STEEL SLAG HANDLING SYSTEM, the latterbeing, in turn, a continuation-in-part of copending application Ser. No.428,519, filed Jan. 27, 1965, entitled STEEL SLAG l-lAN- DLlNG SYSTEM,now US. Pat. No. 3,316,075 and of copending application Ser. No.535,143, entitled STEEL SLAG HANDLlNG SYSTEM, filed Mar. 17, 1966, nowabandoned each of which is a continuation-in-part of earlier applicationSer. No. 126,792, filed June 21, 1961 and now abandoned. Thisapplication is also a continuation-in-part of copending application Ser.No. 632,822, filed Apr. 21, 1967, now US. Pat. No. 3,523,015 andentitled STEEL SLAG HANDLING SYSTEM, the latter also being in turn, acontinuation-in-part of copending applications Ser. No. 428,519 and Ser.No. 535,143 now abandoned.

Reference is also made to my copending U.S. Pat. application Ser. No.629,755, filed Apr. 10, 1967, now U.S. Pat. No. 3,531,270 and toapplication No. 632,825, filed Apr. 21, 1967, now U.S. Pat. No.3,531,269 both of which applications are directed to various portions ofthe system described herein. Insofar as pertinent, all of theabove-identified US. patent applications are to be considered asincorporated by reference in the present application.

THE INVENTION The present invention relates to an improved system forprocessing and disposal of molten slag discharged from a steelmakingfurnace. More particularly, this invention relates to an open systemmethod and apparatus for granulating and cooling molten steel slag byinteraction with one or more jets of water under certain specifiedconditions, then removing the granulated slag from the granulator as aslag-water slurry and subsequently removing the water to convert theslag to a substantially dry granular form. This invention isparticularly adapted for use in an area where large quantities ofrelatively cool water are conveniently available and thus includesfacilities for effective water filtration to permit disposal of thegranulating and cooling water by direct discharge into nearby rivers.

As discussed in considerable detail in the aforementioned parentapplications Ser. Nos. 428,519 and 126,792, and re lated applications,the efficient, quick removal of large quantities of molten slag fromopen hearth and other steelmaking furnaces and the processing thereof isa long standing major problem in the manufacture of steel. A tremendousamount of slag must be removed from the furnace each day and efficientlyprocessed without interruption of furnace operation if maximumsteelmaking capacity is to be realized.

The problems of handling and removing steel slag have been seriouslyincreased by the US. steel industrys rapid adoption within the pastseveral years, of oxygen steelmaking furnaces, sometimes referred to asOSM of BOF furnaces. These furnaces are capable of producing steel ineven larger quantities in shorter periods of time than many of the mostup-todate open hearth installations. For example, one steel company inthe United States has produced about 240 tons of steel in 27 minutes,tap-to-tap, compared to 68 hours in modern open hearth furnaces. Suchoxygen steelmaking furnaces form large quantities of slag, e.g., on theorder of 12-16 percent of the heat tonnage. Thus, an OSM or BOF furnaceproducing about 200-250 tons of steel in 3060 min. will also produce asmuch as 35 tons of molten slag in 30-60 minutes. Such large quantitiesof molten slag must be rapidly removed and disposed of, withoutinterruption or delay in the operation of the furnace.

As further described in detail in parent application Ser. No. 428,519,the steel making industry has employed numerous systems for slagprocessing and disposal. One such technique involves discharging themolten slag into slag pots which are transported by means of cranesand/or rail cars from the furnace to a relatively remote disposallocation. Further processing of the slag for metal recovery or roadbuilding, etc., requires that the solidified slag be broken up fromrelatively large pieces with extra equipment at substantial cost.

As amplified in the aforementioned parent application such multistepbatch methods of handling molten slag are not only costly from theviewpoint of slag handling, but also have serious inherent shortcomingswhereby improvement on such methods is essential to minimize or avoidproduction delays, and is a matter of serious concern to the entiresteelmaking industry.

The invention described in parent application Ser. No. 428,519, is asteel slag granulating system including method and apparatus whichpermits substantially continuous processing and removal of steel slagdischarged from the furnace without delay in the steel making process.In particular, the steel slag granulating system of my parent casescomprises a receptacle into which the red-hot molten slag from the steelfurnace is discharged and in which it is suddenly cooled and granulatedby jets of water injected into the granulator to intercept the stream ofmolten slag. The result is the formation of relatively small, discreteparticles of granulated slag which may then be discharged from thegranulator and transported by continuous mechanical or hydraulicconveyor means to a suitable storage or disposal facility. v

The subject matter of the present application is an open hydraulic steelslag granulating and processing system incorporating the granulatordescribed above. In the present system, granulation and cooling of themolten steel slag in the above-described manner is followed by theconvenient transportation of the slag from the granulator in the form ofa water-slag slurry and the subsequent separation of the water and thegranulated slag. The dried slag may then be stored, e.g.,-in bins or inthe open pits or directly on the ground, prior to further processing,use or other disposal.

As amplified below, proper operation of the basic granulating systemrequires the availability of substantial quantities of relatively coolwater, both to minimize evolution of steam and also to achieve effectiveand safe steel slag granulation. Accordingly, after the granulated slagparticles have been extracted from the slag-water slurry, it may benecessary to dispose of extremely large quantities of spent water. Incopending application Ser. No. 632,822 filed Apr. 21, 1967, there isdisclosed a closed hydraulic system in which the problems of disposal ofsuch water are obviated by the employment of a water recirculationsystem in which the water is continually reused in the operation of thegranulator system. The closed hydraulic arrangement is especiallyattractive, not only due to the elimination of water disposal problems,but also since it reduces considerably the amount of water necessary forsatisfactory granulator operation.

On the other hand, the closed hydraulic system is somewhat complex andrequires efficient means for substantially cooling the previously usedwater before reuse. Where it is possible to filter the used water in aneffective and economical manner, e.g., to comply with local ordinancespertaining to the disposal of industrially used water, and whererelatively large quantities of water are freely available for use in thegranulator system, an alternative to the above-mentioned closedhydraulic granulator system is quite desirable. An open hydraulicsystem, in which the water is efficiently separated from the granulatedslag and properly filtered to permit disposal in nearby sewers orrivers, is the subject of the present invention.

Accordingly, it is a general object of the present invention to providea further improvement of the steel slag granulating system described inparent application Ser. No. 428,519.

1t is a more specific object of this invention to provide an improvedsteel slag granulating system in which molten steel slag transportedfrom the steel making furnace is discharged into a granulator system toform a slag-water slurry from which a substantial portion of water issubsequently removed,

whereby the granulated slag may be stored or disposed of insubstantially dry form.

It is a related object of this invention to provide a granulator systemas described above in which the water extracted from the slag-waterslurry is processed to render it sufficiently clean so that it may bedisposed in nearby sewers or rivers without additional treatment.

The exact nature of this invention as well as other objects andadvantages thereof, will become apparent from consideration of thefollowing detaileddescription and the accompanying drawing in which:

FIG. 1 is a schematic side elevation, partially cutaway to reveal theessential features of the molten slag feeding, cooling and granulation,and hydraulic transport portions of the slag handling system of thisinvention;

FIG. 2a is an enlarged, fragmentary view of a portion of FIG. 1 showingthe construction of the pouring opening and the slag feeding vessel;

FIG. 2b is an enlarged view of a further portion of FIG. 1 illustratingthe construction and assembly of the water jet nozzles;

FIG. 3 is a top plan view of the portion of the system shown in FIG. ll;

FIG. 4 is an end elevation of the portions of the system of FIG. 1showing the portion of the system from which the granulated slag isdischarged;

FIG. 5 is a generally schematic view of the slag drying and waterfiltration portions of the system in which the dewatered slag isdirectly stockpiled in relatively dry form;

FIG. 6 shows the manner in which FIGS. 1 and 5 are to be arranged toform an overall schematic view of the system of the present invention;and

FIG. 7 is a generalized schematic view of one suitable modification ofthe drying and water filtration portions of the system which may besubstituted for the arrangement shown in FIG. 5, and which provides sizeclassification of the granulated slag prior to stockpiling.

Referring now to the drawings, and in particular to FIGS. 1-4, thegranulating portion of the present invention denoted generally byreference numeral 10, includes molten slag feeding apparatus 12, andgranulating apparatus including a pair of similar granulators 14 and 16,disposed adjacent to each other at some convenient location close to thesteelmaking furnaces. Granulators 14 and 16 are fitted with steam hoodsl8 and 20, respectively, for reducing uncontrolled emission of steamgenerated by contact between the red-hot slag and the cooling andgranulating water. Common steam collection and disposal means, generallydenoted as 22, cooperates with steam hoods 18 and 20 to collect steamproduced during granulation and to transport it to a remote point forventing to the atmosphere. As described hereinafter, the granulated slagresulting from operation of granulators l4 and 16 is preferablycollected and removed from the granulator by means of hydraulictransport apparatus generally denoted as 24. Screening means and anoversized particle conveyor 26 are provided to facilitate convenienthandling of large slag particles or other debris which might damage thehydraulic transport apparatus or which, in any event, could not beefficiently transported in the slagwater slurry.

The construction of slag feeding apparatus 12 is illustrated in FIGS. 1,2a, and 3. The arrangement shown is especially useful when location ofgranulator system in extremely close proximity to the steel makingfurnaces is not feasible, e.g., due to space limitations. Here, moltenslag is transported from the steel furnace by means of a refractorylined slag ladle or container 28. This is carried by a remotelycontrolled overhead crane 30 including a pair of spaced lifting hookssuch as 32, adapted to engage a pair of trunnions 34 on opposite sidesof ladle 28. Crane 30 is also fitted with a separate pouring hook 36adapted to engage with a lifting bar 38 secured to the bottom of ladle28 for controllably tilting the ladle on trunnions 34 to discharge themolten slag. Crane 30 is adapted to travel on an overhead track (notshown) into and out of the plane of FIG. I and transversely ofgranulator system 10 in FIG. 3 to permit alignment with either ofgranulators 14 or 16.

An auxiliary vessel 40 supported on a pedestal 42 on the floor 44 of thesteel making shop (or in the surrounding yards) and a similar vessel 46(see FIG. 3) serve as tundishes for feeding molten slag to granulators14 and 16, respectively, with a controlled rate of flow. The contents ofslag ladle 28 may be discharged into either of vessels 40 or 46 bypositioning overhead crane 30 at the proper location along its track.This permits backup use of either of granulators l4 and 16, should theother granulator be disabled. The arrangement also permits two differenttundish setups for two rates of pour of molten slag from crane ladle 28via the tundish into the respective granulators, if desired, for slaghaving different characteristics as occurs for different-type steelheats.

As illustrated herein, tundish vessels 40 and 46 comprise suitablymodified steel slag ladles or blast furnace slag pots, although it willbe appreciated that specifically designed tundish receptacles may beemployed. Tundish vessel 40 includes a slag feeding aperture 48 (seeFIG. 2a) cut into the vessel wall at a predetermined level with apouring spout 50 secured around the opening by welding or in any otherconvenient fashion.

An overflow opening 52 is also cut into the wall of tundish 40, e.g.,diametrically opposite to slag feeding opening 48, and is fitted with anappropriate spout 54. Opening 52 is disposed at a predetermined heightabove opening 48 and permits overflow to the ground or shop floor 44 ifthe level of molten slag in the vessel exceeds that of opening 52.

Hence, if the rate of slag flow into vessel 40 from ladle 28 exceeds therate of discharge through aperture 48, the level of the liquid slag willultimately exceed the level of opening 52. At that time, molten slagwill be discharged to pit 44, thus establishing a maximum slag flow ratefrom tundish 40 through aperture 48 into the granulator 14, Le, amaximum pressure head of molten slag is maintained in tundish 40,thereby controlling the rate at which molten slag enters the granulatorsystem. Further, discharge of slag to pit 44 through upper aperture 52alerts the crane operator to reduce the slag input rate, by loweringpouring hook 36.

With reference to FIG. 3, thesecond tundish 46 is of substantiailyidentical construction as tundish vessel 40, and includes a granulatorfeeding aperture 56, an upper slag overflow opening 60, and a pair ofassociated spouts 58 and 62, respectively. The relationship betweenopenings 56 and 60 is preferably the same as that between openings 48and 52 in vessel 40 to assure like operation of both portions of thesystem. Satisfactory operation may be achieved for openings 48 and 56having configuration and dimensions as shown in FIG. 2a. Openings 52 and60 are preferably both in the form of a square about 4 inches on a side.Under such conditions, satisfactory operation may be achieved with thebottom of openings 52 and 60 vertically spaced approximately 2-4 inchesabove the tops ofopenings 48 and 56.

The configuration of openings 48 and 56 illustrated in FIG. 2a ispreferred because the lower square section 4812 establishes the desiredrate of slag flow having a head equivalent to the height of section 48a.The flaring upper section 48b provides a linearly increasing aperturearea per unit of height from the bottom to the top of section 48b due tothe increasing transverse dimension. The increasing area causes thevelocity of the molten slag leaving tundish 40 to decrease from thebottom to the top of section 48b so that the molten slag will. not havetoo long a trajectory in relation to the dimensions of granulator l4 andchute 64.

In this regard, it should be appreciated that the 4 inch head specifiedbetween openings 48 and 52 may be achieved by location of opening 48 atthe required distance below the lip 61 at the top of vessel 40. In thatcase, a small notch is preferably provided at the back of the vessel tolimit overflow to the region of the ground or pit 44 behind the vessel.

The above-described slag feeding apparatus 12 is exemplary of apreferred embodiment but several alternative approaches could be used inlight of the disclosure herein. For example, the granulator slag feedingarrangement could incorporate a movable slag runner which can bedisplaced from association with a slag ladle or like means used fortransferring the slag directly from the steel furnace to the granulatorutilizing slag runners or chutes analogous to those disclosed in myparent application Ser. No. 428,5 l 9, or in copending application Ser.No. 551,168, filed May 18, 1966, and entitled Steel Slag HandlingSystem," now U.S. Pat. No. 3,316,079.

Referring to FIGS. 1 and 3, the slag feeding arrangement employed shouldpreferably terminate in.a refractory lined steel discharge chute 64associated with granulator 14, and a like discharge chute 66 associatedwith granulator 16. Chutes 64 and 66 are supported by any convenientsupport means (omitted from the drawings to show the other parts moreclearly) and project into granulator receptacles 14 and 16 throughsuitable openings in the end walls.

As amplified below, it is preferable that the streams of molten slagflowing into the granulators possess minimum velocity componentstransverse to the primary flow direction, i.e., longitudinally of thechutes. Accordingly, discharge chutes 64 and 66 are formed in anyconvenient manner with sloping bottom portions 68 and vertical sideportions 70. When side portions 70 include inwardly tapered segmentssuch as 72, e.g., to accommodate placement of tundish spouts 50 or 58.The chute should include terminal straight-sided portions 74, preferablyat least about 1 foot in length to minimize the trajectory of the moltenslag transverse to the overall flow direction. Chutes 64 and 66 lie at asuitable-angle relative to the horizontal so that the flow of slag intothe granulators is gravity assisted. The angle may be substantially asillustrated in FIG. 1, but can be varied according to varying viscosityof particular molten steel slags, as will be understood in light of thedisclosure herein.

With continued reference to FIGS. 1-3, each of granulators 14 and 16 iscomprised of a boat-shaped tank or receptacle preferably fonned of aplurality of steel plates welded or otherwise secured together to form awatertight structure. With reference to FIG. 1, the side of granulator14 shown is constructed of a number of steel plates such as 76, 78, 80,and 82, welded together in a conventional manner to form an elongatedsidewall. The opposite side of granulator 14, as well as the two sidesof granulator 16, are similarly constructed. The bottom of granulator 14is formed of a sloping plate 84 at the upstream (input) end of thegranulator, a substantially horizontal rectangular plate 86 forming thecentral portion of the granulator bottom and a further slopingrectangular plate 88 forming the downstream (discharge) end of thegranulator. Plates 84, 86, and 88 are welded to the sides of thegranulator in a conventional manner to form a watertight receptacle asmentioned above.

Secured to the upstream sideplate 76, to bottom plate 84, and to thecorresponding opposite sideplate (not shown) of granulator 14, is an endplate 90, which defines the end closure for granulator 14, and alsoserves to support a plurality of granulating jet nozzles as describedmore fully below.

The entire granulator structure is supported by a steel frameworkincluding a plurality of spaced vertical legs 92 on both sides of thereceptacle and a pair of like side frame members 94, at the top of thereceptacle, secured to legs 92 and to the sideplates 76,78, etc. Legs 92are arranged to rest on floor vessel 40 to achieve the desired slope forchute 64. As will be understood, a like construction is employed forgranulator receptacle 16.

With reference to FIG. 2b, granulating and cooling water is injectedinto granulator 14 by means of a plurality of nozzles including a pairof vertically spaced horizontal nozzles 96 and 98 and a pair ofhorizontally spaced vertical auxiliary nozzles 100 and 102 positioned atthe sides of upper primary nozzle 96 (see FIG. 3). Nozzles 96, 98, 100,and 102 are connected by means of a conduit 103 (see FIG. 1) to a commonwater feedpipe 105. Granulating water may be obtained from anyconvenient source such as the local water mains or a nearby river. Awater pump 106 of conventional design connected by pipe 107 to the watersupply, provides thegranulating and cooling water through commonfeedpipe in the required quantities as amplified below.

A water strainer 108, e.g., a Y-pattern sediment strainer such asmanufactured by the V. P. Anderson Company of Cleveland, Ohio, or theAloyco" Y-type strainer, manufactured by the Walworth Company of NewYork City, N.Y., is inserted in feedpipe 105 to remove any debris whichmight obstruct nozzles 96,- 98, 100, and 102. Strainer 108 should becapable of removing all particles of size equal to or greater than thesmallest dimension of granulating nozzles 96, 98, 100, and 102, e.g.,less than inch in the specific example described below. Use of waterstrainer 108 is desirable since even a small particle obstructing thetips of the granulating nozzles may cause the injected water jetstreamto be split, whereby enough molten steel slag may fall directly into.the granulator without undergoing the granulating and cooling effectsof the water jets to present a danger of explosion. A conduit 104,similar to conduit 103, provides the water supply to four nozzles ingranulator 16 of substantially identical construction as nozzles 96, 98,100, and 102 in granulator 14.

An extensive discussion of the construction and assembly of nozzles 96,98, 100, and 102, and of pertinent relationships therebetween, may befound in several of the aforementioned copending applications, e.g.,Ser. No. 428,519 and Ser. No. 632,825, and therefore is not repeatedherein. Briefly, however, the input ends 97 and 99 of primary nozzles 96and 98 are connected to conduit 103 by short connecting pipes 109 and111. The nozzles are constructed in any suitable fashion, e.g., of aplurality of welded metal plates, and are designed to producesubstantially uniform jet streams at the discharge orifices 110 and 112.I

Nozzles 96 and 98 project through a pair of slots 114 and 116 ingranulator end wall 90. The nozzles are supported in any convenientmanner, e.g., by means of a pair of rearwardly depending brackets suchas 118 secured as by welding to opposite sides of the granulator endwall 90 and each terminating in an outwardly turned flange such as 122at the rear end thereof. A pair of like vertically spaced rectangularmounting plates 124 are secured to flanges 122. A rectangular slot 128is cut in each of plates 124 to receive nozzles 96 and 98 with thedischarge ends projecting slightly beyond granulator end wall 90 asshown in FIG. 2b.

In regard to the configuration of the nozzles, it has been found thatmost satisfactory operation is achieved when the stream of molten slagdischarged into granulator 14 through discharge chute 64 intercepts abroad, flat, generally horizontal jetstream of water produced by each ofprimary nozzles 96 and 98, the jetstreams being somewhat wider than thestream of slag. The vertical thickness of the flat, horizontal waterjets may be quite small. Thus, discharge openings 110 and 112 of primaryhorizontal nozzles 96 and 98 are preferably in the form of narrow,rectangular slits having the longer dimensions thereof extendingtransversely of granulator end wall 90, i.e., into the plane of thedrawing in FIG. 2b. While the dimensions of discharge openings 110 and112 may be subject to some variation, excellent results have beenachieved with horizontal nozzles 96 and 98 having discharge openingsapproximately inch high, and about l4, 18, or 22 inches wide. Detaileddiscussion of horizontal primary nozzles like 96 and 98 may be found inthe aforesaid parent applications Ser. No. 428,519 and Ser. No. 126,792.Obviously, similar considerations apply to the primary horizontalnozzles associated with granulator 16.

As explained in the parent applications, other factors are significantin achieving a satisfactory or even an operative system with the basicgranulator arrangement. One such factor is the relationship between'themolten slag input rate and the velocity and quantity of water injectedthrough primary nozzles 96 and 98. It has been found that the steel slaggranulation system of the present invention preferably should beoperated according to certain conditions as set forth below.

1. In particular, normal steel making operations are found to result inthe discharge of molten slag at rates varying from less than about 2tons per minute up to as high as about 8 tons per minute. Under suchcircumstances, granulating water should be supplied through primarynozzles 96 and 98 such as described above with a jet velocity in feetper second and a flow in gallons per minute which varies in relation tothe rate at which the molten slag is discharged into the granulator. Asuitable relationship between varying rates of slag input and thevelocity and flow of granulating and cooling water through a singlenozzle, i.e., upper nozzle 96, is given in Table l below.

Minimum Water Requirements Primary Nozzle 96 Only The velocities givenin Table 1 are based on injection of the entire stated minimum waterquantity through upper nozzle 96. If both horizontal nozzles 96 and 98are to be employed, the specified flow may be provided by the combineduse of both nozzles. In that case, the jet velocities will be 36.5-35f.p.s. for slag inputs of between 4 to 7 tons per minute, and 55-61f.p.s. for a slag input of 7 to 8 tons per minute. However, thevelocities for slag inputs of up to 4 tons per minute are preferably atleast those given in Table One whether using one or two granulatingnozzles.

2. For most satisfactory operation, it is found that the total quantityof water supplied to receptacles l4 and 16 during operation shouldexceed the minimum required for injection through nozzles 96 and 98. infact, the total quantity of water introduced should be at least about400 gallons of water per minute per ton of steel slag per minutedischarged into the granulator. Preferably, however, water should beintroduced at a higher rate, e.g., about 900 to 1,350 gallons of waterper minute per ton of steel slag per minute discharged into thegranulator. Most satisfactory results, in terms of minimum vaporizationof granulating and cooling water, are achieved by introduction of atleast about 1,350 to 1,600 gallons of water per minute per ton of steelslag discharged per minute. The input water should preferably be at anytypical water main temperature, e.g., 60-70 F. However, furnace coolingwater or other plant used water may be employed having a tempera ture ofabout 100 F. or above, if necessary.

3. Generally, it is preferable that the water requirements set forth inParagraph 2 be satisfied by supplying all water through primary nozzles96 and 98, or, as amplified below, partially through auxiliary nozzles100 and 102 as well. Where the auxiliary nozzles are not employed, andif the requirements of Table One can be met with a lower quantity ofwater through nozzles 96 and 98 than the total required by Paragraph 2,the excess may be supplied by other means, e.g., a water pipe ofsuitable size may be secured to end wall 90 of granulator receptacle 14below nozzles 96 to supply additional water to the receptacle by conduitfrom a suitable source. However, the safest and best approach is tointroduce all the required water through nozzles 96 and 18. Thisincreases the effectiveness of the water jets for breaking down themolten steel slag into small particles to achieve more rapid and moreefficient slag cooling and granulation, and helps assure smallerresultant granulated slag particles for more efficient hydraulic slurrytransportation as amplified below.

4. In light of the foregoing, good results can be achieved by injectingtwo jetstreams of water into granulator receptacles 14 and 16 throughprimary nozzles 96 and 98 according to the following: (a) For moltenslag input of up to about 2 tons per minute, inject two water streamswith jet velocity of about 36.5 to 61 f.p.s., and about 1,200-200 g.p.m.through both jets. (b) For a molten slag input rate of 2 to about 4 tonsper minute, inject two water jetstreams at a velocity of at least 61 to122 f.p.s., and about 2,000-4,000 g.p.m. through both jets. (c) For amolten slag input rate of 4 to about 7 tons per minute, inject two waterjetstreams at a velocity of at least about 91 to 146 fps, and about3,000-S,000 g.p.m. through both nozzles.

Auxiliary vertical nozzles and 102 are constructed generally similar toprimary horizontal nozzles 96 and 98. As illustrated in FIG. 2b, sidenozzle 100 projects through a generally rectangular aperture 134 ingranulator end wall 90, while nozzle 102 projects through a likeaperture on the opposite side of granulating nozzle 96. Short connectingpipe segments of like construction are provided between the input ends132 of the auxiliary nozzles 100 and 102 and common water conduit 104.The nozzles are supported in any suitable fashion, e.g., with connectingpipes 130 projecting through a pair of apertures 135 and plate 124 andan aligned pair of apertures 136 in flanges 122 in mounting brackets118.

As in the case of granulating nozzles 96 and 98, most satisfactoryoperation for side nozzles 100 and 102 is found to result for nozzledischarge openings 137 having generally narrow elongated cross sections.The nozzles are so positioned that the jet stream issuing throughdischarge orifice 110 of upper primary nozzle 96 lies intermediate theupper and lower edges of the streams issuing from side nozzles 100 and102. Preferably, however, horizontal nozzle 96 is so disposed that thejetstream issuing therefrom lies at or below the center of streamsissuing from the vertical side nozzles to produce a combined waterstream having a generally U-shaped cross sec tion. (The latter term isintended to include the specific H- shaped cross section shown in FIG.2b.)

Further details of the above-described construction, as well as anextensive discussion of its advantages, may be the abovereferred tocopending application, Ser. No. 632,825. Briefly, however, as describedtherein under many circumstances the stream of molten slag beingdischarged into the granulator is found to possess a trajectoryincluding substantial velocity components transverse to the primarydirection of slag stream flow. Such a condition results in portions ofthe slag stream failing to intercept the horizontal jetstreams producedby noz zles 96 and 98 with resulting nonuniform granulation and coolingof the molten slag. By employment of the vertical side nozzles 100 and102, transversely moving portions of the slag stream intercept thevertical portions of the water jet, while the main body of the slagstream continues to intercept the horizontal water jets. This has beenfound to improve the uniformity of system operation under theabove-mentioned condition.

The flow rate and jet velocity of the water injected through auxiliarynozzles 100 and 102 is found to be governed by the variousconsiderations discussed above in connection with nozzles 96 and 98 inthe paragraphs numbered 1-4. However, because the portion of the streamof molten slag having the undesirable transverse trajectory is small incomparison to the overall slag tonnage, the required flow rate and jetvelocity is less than the minimum specified in Table One above.

5. Specifically, it is found that satisfactory operation is achieved ifat least about 60 percent, and preferably about 70 percent, of the totalwater supplied to the granulators is equally divided between the primarynozzles 96 and 98, with the remaining quantity being equally dividedbetween auxiliary vertical nozzles 100 and 102. Again, it should beemphasized that the requirements of Paragraph 1 above must be met in anyevent. Thus, with reference to Paragraph 4 above, good results areobtained, with the added benefit of improved granulation of transverselyflowing slag, if water is injected into the granulator with a minimumrate of flow and minimum velocity through the various nozzles dependingupon the rate of molten slag input to the granulator in accordance withTable 2 below:

Slag Input Nozzles 96 and 98 Nozzles I and 102 (tons/mir|,) vel. (fps)flow (gpm) vel. (fps) flow (gpm) Up to 2 25-42 420-700 19.2-32 180-3002-4 42-84 700-1400 32-64 300-600 4-7 65.5-105 1100-1750 48-80 450-750TABLE 2 Water Requirements For Preferred Operating Conditions Nozzles96, 98, 100, and 102 6. By way of example, the following conditions arerepresentative of suitable operation of an O.S.M. steel slag granulatingsystem in accordance with this invention, under typical conditions: Atotal quantity of as much as 37.5 tons of molten O.S.M. Steel slag maybe discharged into the granulator system over a period of approximately-11 minutes; there may be significant variation in the sought-foraverage 3.5 tons per minute rate for slag poured into the granulator dueto practical difficulty in getting a precisely controlled pour. Undersuch conditions, water is provided to the granulator at the rate ofapproximately 3,500-4,000 gallons per minute. Of this, approximately2,800 gallons per minute is provided by the horizontal nozzles 96 and 98with approximately 1,400 g.p.m. injected through each nozzle at avelocity of about 84 fps. The remainder, i.e., approximately 1,200g.p.m. is equally divided between vertical nozzles 100 and 102, and isinjected at a velocity of about 64 fps. Of course, it should berecognized that the above-described nozzle construction and mode ofoperation is employed in granulator 16, as well as in granulator 14.Accordingly, in the interest of brevity, further description of thisaspect of the invention will be omitted herein.

Granulators l4 and 16 are so constructed that a portion of the waterentering the granulator through nozzles 96, 98, 100, and 102 is retainedat the bottom of the receptacle in the form of a relatively shallow bath142. The level of bath 142 is controlled by overflow means 144comprising an aperture 146 out into one of the granulator sideplates,such as 80, at the desired bath level. A water overflow chamberconstructed of a plurality of welded plates is secured around overflowopening 146 and is connected to an overflow pipe 148 for disposing ofthe excess water in any convenient manner.

As explained in parent application Ser. No. 428,519, the presence ofwater bath 142 is quite desirable in providing additional cooling forthe granulated slag but the bath is maintained at a level below thelower primary nozzle 98 to assure that the molten slag intercepts thegranulating jets at a level above the bath.

As will be appreciated, suitable means must be provided to move thegranulated slag particles from the vicinity of the granulating nozzlesand also from the granulator receptacles themselves. One arrangement forachieving this result is a continuous rake conveyor generally designatedat 150 in granulator 14. Rake conveyor 150 comprises a plurality ofendless chains 154 (e.g., 3) and a series of attached rectangular steelflights 156 which serve as scrapers or rakes for the granulated slagparticles. Chains 154 are supported by means of a plurality of drivesprockets 158 rigidly secured to a drive shaft 160 at the upstream endof the granulator receptacle, and by a plurality of idler sprockets 162secured to an idler shaft 164 at the downstream or discharge end of thegranulator. Shafts 160 and 164 are rotatably supported in suitablebearings mounted in any convenient fashion at the side of the granulatorreceptacle. Drive shaft 160 is connected, either directly or indirectly(as by a conventional pulley and belt arrangement), to a suitable drivemotor (not shown), mounted in a protective housing 166 on one side ofthe granulator receptacle. As will be seen from FIG. 4, a similarlyconstructed rake conveyor 152 is employed in granulator receptacle 16.However, it should also be understood that other functionally comparableslag removal means could be employed instead of the rake conveyorsillustrated.

The granulated slag particles are carried by the leading surfaces ofmoving rake flights 156 along the bottom of the granulator and up alongsloping bottom plate 188 for further processing in the manner now to bedescribed.

As previously indicated, the preferred means for removing the granulatedslag particles from the granulator receptacles 14 and 16 is a hydraulicpumping arrangement wherein the granulated slag is transported in theform of a water-slag particle slurry. Accordingly, the system of thepresent invention includes hydraulic transport system 24 having anauxiliary mixing tank 168 and a slurry pump 170, commonly associatedwith granulators l4 and 16 as illustrated in FIGS. 1 and 4.

Granulated slag particles are carried by rake conveyors and 152 to thedownstream end of the granulators and onto the sloping granulator bottomplates 88. From here, the slag particles and a substantial portion ofthe injected water are discharged into mixing tank 168 through aplurality of perforations 172 in bottom plates 88. Funnel means 174,constructed of a pair of triangular side plates 176 and a rectangularend plate 178, is attached to bottom plates 88 to guide the slagparticles and the water into mixing tank 168. As will be apparent fromFIG. 4, a second funnel means 175, identical to funnel means 174, isassociated with a perforated bottom plate (not shown) in granulatorreceptacle 16 identical to perforated bottom plate 88 in granulatorreceptacle 14, to guide the granulated slag from receptacle 16 intocommon mixing tank 168 as explained above.

The perforations in the sloping bottom plates 88 are chosen to screenmixing tank 168 against the entry of material of greater than apredetermined size to prevent possible damage to the pumping system andalso, since extremely large particles cannot efficiently be transportedin the form of a slurry. in practice, perforations 172 may be formed toadmit slag particles having a maximum size of about 2 inches.

The larger material not passing perforated plates 88 continues to bedisplaced upwardly by the leading edges of the rake conveyor flights 60until the particles are propelled out of the granulator receptacles 14and 16 through openings and 167 at the downstream ends. The oversizedslag particles fall onto oversized particle conveyor 26, as illustratedin FIGS. 1, 3, and 4, supported by any convenient means, (omitted fromthe drawing for clearer illustration of other parts), adjacent to theend openings 165 and 167 of the granulator receptacles.

Oversized particle conveyor 26 is preferably a motor-driven continuousbelt conveyor of any commercially available type, such as those commonlyused in gravel pits or quarries. One suitable type is the Telsmith B-GContinuous Conveyor, manufactured by the Smith Engineering Works,Milwaukee, Wis. Since such devices are readily available, detaileddescription of their construction is not necessary. In any event, itwill be understood that the oversized slag particles are carried alongby conveyor 26 to the desired location for disposal or temporary storageas shown in FIG. 4. Under most conditions, however, it is found that alarge portion of the granulated slag passes through perforated plates 88and only a small percentage, e.g., less than one percent must be handledby the oversized particle conveyor 26.

Referring again to the hydraulic transport system 24, the slag-waterslurry collecting in mixing tank 168 is removed by means of a largediameter abrasion resistant pipe 180 communicating with the interior ormixing tank 168 through an aperture 182 at the bottom of one of the tanksidewalls.

The discharge end of pipel80 is connected as the input to a dredge pumpwhich is preferably a commercially available, heavy-duty, centrifugalpump of any suitable design, such as the Morris-type IOGMA-28. Thelatter, driven at about 1,150 rpm. by a suitable motor 171 ofapproximately 200 hp. capacity, is capable of handling a slurry flow ofabout 3,500-4,000 g.p.m. plus a solid (i.e., slag particle) content of3-4 tons per minute.

As shown in FIG. 1, connecting pipe 180 preferably includes an elongatedvertical portion 184 whereby pump 170 is disposed a substantial distancebelow the bottom of mixing tank 168. This is desirable to provide apressure head at the inlet of pump 170 to minimize inefficiency andsealing or related problems which may arise in the operation of pump 170when the water-slag slurry in mixing tank 168 is at a highly elevatedtemperature, e.g., approaching the boiling temperature of water. As willbe appreciated, under certain circumstances, dredge pump 170 may belocated on a lower floor of the steel making shop to provide the desiredhead with respect to the mixing tank. Alternatively, as where it isnecessary to locate the granulator system in the yard between shops, therequired head may be achieved by locating pump 170 in a well 186 dug outbeyond the downstream end of the granulator receptacles 14 and 16. Pump170 is connected by means of a large diameter abrasion resistant outletpipe 188 to the dewatering and slag disposal portion of the system shownin FIGS. and 7, and described in detail below.

The hydraulic slurry pumping system 24 is described in considerabledetail in aforementioned copending application Ser. No. 535,143, and inthe interest of brevity, such description is omitted here. However,certain significant operating conditions have been discovered whichshould be satisfied for optimum utilization of the slurry pumpingsystem.

It is found that factors pertinent to most desirable operation includethe minimum slurry velocity in discharge pipe 188, the concentration ofsolids in the slag water slurry and the slurry temperature inrelationship to the head at the input of pump 170. I

It is found that best operation is achieved with: (a) minimum slurryvelocity in discharge pipe 180 of at least about 17 feet per second; (b)the weight of solids suspended in the slurry not significantly exceedingabout 17 percent; and (c) a slurry temperature in mixing tank 168 notsignificantly exceeding approximately l85 F. (e.g., up to approximately200 F.

While many complex factors are significant in design of the system tomeet the above requirements, it has been found that adjustment ofseveral parameters results in quite satisfactory operation.Specifically, it is found that for the Morris-type pump 170 operating inthe manner described above, input pipe 180 should have an insidediameter of at least about 12 inches and should include a verticalportion 184 to establish a head of about between and 18 feet on the pumpinput. An output pipe 188 should have an inside diameter ofapproximately 9 inches, and may be of substantial length, e.g., as muchas 1,700 feet or more.

In regard to the concentration of solids in the slurry, it will beappreciated that the rate of flow of molten slag into the granulatorreceptacles 14 and 16, as well as the water input through the jetnozzles 26-30 are significant factors which must be correlated toachieve the desired water to slag ratio. One suitable technique foradjusting this ratio is to control the concentration of the slurry inmixing tank 168 by injecting additional water as necessary. This may beaccomplished by any suitable valve-controlled piping, not shown in theinterest of clarity. Likewise, the temperature of the slurry can becontrolled by the injection of additional cooling water into mixing tank168.

However, control of the solids concentration, as well as the temperatureby injection of sufficient quantities of water into the granulatorreceptacle itself by the jet nozzles, is preferred as set forth morefully in the aforementioned application, Ser. No. 535,143.

As previously mentioned, granulator receptacles l4 and 16 are fittedwith steam hoods 18 and 20, respectively, to prevent the uncontrolledemission of steam generated during the granulating process. As explainedin detail in my copending application Ser. No. 629,755, this isextremely desirable since maximum efficiency in the operation of thegranulating system requires its location in as close as possibleproximity to the steelmaking furnaces. Uncontrolled venting of steam insuch areas may pose an inconvenience or even a safety hazard for nearbyworkers.

Steam hood 18 is comprised of a side frame 190 having a pair ofelongated side members 192 as best illustrated in FIG. 3. The upstreamends of side members 192 each terminate in a downwardly dependingportion 194 secured to granulator end wall as shown in FIG. 2. At thedownstream end side members 192 each terminate in an angle portion 196having a sloping upper leg 198 and a second substantially vertical leg200 secured at the extreme end of downstream sideplate 82.

With reference to FIGS. 1 and 3, the top of steam hood 18 is formed of aplurality of substantially rectangular cover plates 202 connectedtogether in any suitable fashion, as by a plurality of upwardly turnedperipheral flanges 204 butt-welded together and to side frame members192. Similarly, the sides of steam hood 18 are formed of a plurality ofgenerally rectangular plates 206, secured together and to side framemembers 192 by a plurality of butt-welded peripheral flanges 208.

Best results are obtained if steam hood 18 does not completely close offthe top of granulator receptacle 14. Accordingly, a pair of smallrectangular plates 210 are secured to the adjacent ones of plates 202and to side frame members 192 in the manner described above. Plates 210are positioned in spaced relationship as shown in FIG. 3, at theupstream end of the granulator to define a recess 212 which exposes slagdischarge chute 64 to the atmosphere.

No vertical plates corresponding to plates 206 are positioned on thesides of discharge chute 64 so that the entire end of the granulatorreceptacle above end plate 90 is exposed to the atmosphere.

At the downstream end, a narrow transversely elongated cover plate 214is secured between upper legs 198 of side frame end portion 196.However, as shown in FIG. 4, the area between vertical leg portions 200of frame end portions 196, is completely open to define the dischargeopening 167 above sloping bottom plate 88. This permits free inflow ofair to the granulator receptacle, as amplified below.

As will be appreciated from FIGS. 1-4, construction of steam hood 20,associated with granulator receptacle 16, is substantially identical tothat described above in regard to steam hood 18.

One of the cover plates 202 at the downstream ends of each of granulatorreceptacles 14 and 16 is provided with a generally rectangular opening216. Surrounding each opening is an upwardly projecting connectingcollar 218 formed in any suitable manner, e.g., of a short length ofrectangular metal ducting having an inner lining of a suitable alkalineresistant material. A common breeching 220 (see FIG. 4), having aninverted V-shaped configuration, is attached as by pairs of weldedflanges 222 and 224 to the respective connecting collar portions 218 onsteam hoods 18 and 20.

Breeching 220 is formed of a pair of separate arm portions 226 and 228welded or otherwise secured to a central connecting portion 230 at theupper ends. Each arm terminates in a short vertical segment 232 at thelower ends, which segments are attached to the respective connectingcollar portions 218 on steam hoods 18 and 20.

Arms 226 and 228 and central connecting portion 230 are formed ofappropriate lengths of metal ducting, e.g., having a square crosssection 8 inches on a side, and having an internal lining of alkalineresistant material. Breeching 220 is constructed of sufficiently heavygauge metal to form a substantially self-supporting structure, and mayadditionally be supported by suitable bracing (not shown) if necessary.

Central connecting portion 230 terminates in a vertical collar portion234 to which is attached a tubular metallic exhaust conduit or stack236, for example, by means of a pair of buttwelded flanges 238. As shownin FIGS. 1 and 4, exhaust stack 236 is of relatively short length;however, it should be understood that a greatly extended exhaust conduitmay be necessary to reach a sufficiently remote location for convenientand safe venting of the collected steam.

From the foregoing, it may be seen that steam exhaust system 22,including steam hoods 18 and 20, breeching 220, and exhaust stack 236,cooperate to form a temporary collection chamber and disposal conduitfor the generated steam.

The construction illustrated in especially convenient for use with apair of adjacent granulator receptacles such as 14 and 16. On the otherhand, should more than two granulators be employed in side-by-siderelationship, breeching 220 may readily be modified to includeadditional arms, one communicating with each granulator.

The collected steam may have some tendency to rise through breeching 220and exhaust stack 236 of its own accord. However, due to the largequantities of steam which may be generated under certain granulatoroperating conditions, a forced ventilation system for breeching 220 andstack 236 is preferably employed.

One suitable type of forced ventilation system would be a directarrangement in which a simple air pump or fan is disposed within exhauststack 236 for drawing the collected steam out of breeching 220. On theother hand, because of the corrosive and abrasive nature of the fineparticles which may be carried in the steam, an indirect arrangement inwhich the moving parts of the ventilating system are not themselvessubjected to the steam, is preferred.

Accordingly, an aspirator arrangement 240, illustrated in H68. 1, 3, and4, is included in steam exhaust system 22. Aspirator 240 comprises ablower 242 driven by an electric motor 244 in any conventional manner.Blower 242 is coupled to a narrow elongated injection tube 246 whichextends from the output of the blower through an aperture 248 in thebottom of central connecting portion 230 a substantial distance, e.g.,several feet, into exhaust stack 236. The construction and operation ofaspirator 240, as well as of the other abovedescribed portions of steamremoval means 22, is discussed in considerable detail in theabove-mentioned copending application Ser. No. 629,755, and suchdetailed description is omitted here in the interest of brevity.

in short, operation of blower 242 causes a relatively highspeed streamof air to be emitted from injection tube 246 into exhaust stack 226. Therapid movement of this airstream establishes a region of depressedpressure in the exhaust stack which is communicated through arms 226 and228 of breeching 220, and openings 216 in steam hoods 18 and 20, toproduce a pressure differential between the interior of the steam hoodsand the breeching. The resulting airflow from the open ends of the steamhoods l8 and 20 into breeching 220 results in the steam generated duringgranulator operation being drawn up through the breeching and on intoexhaust stack 236.

As mentioned above, large quantities of steam may be generated undercertain conditions of granulator operation, and exhaust system 22 mustbe capable of satisfactory operation even at these times. Among thefactors which have been found to affect the quantity of steam generatedare the nature and flow rate of the molten slag, and the velocity, flowrate, and temperature of the water injected through the jet nozzles. Aswill be appreciated, satisfactory operation requires proper correlationof the variable design parameters for exhaust system 22 with theabove-described operating variables. These factors are discussedextensively in the aforementioned application Ser. No. 629,755,particularly in terms of the volumetric exhaust capacity of theaspirator 240 and the associated exhaust conduit 236. In general, it isfound that a minimum steam exhaust capacity varying from less than about1,000 cubic feet of steam per minute under ideal conditions to about300,000 cubic feet of steam per minute for most severe conditions, isnecessary.

Referring now to FIG. 5, there is shown the slag dewatering andstockpiling, and the water filtration and disposal portions of thesystem generally denoted at 250. Subsystem 250 comprises slag dewateringapparatus 252, a stockpiling conveyor 254, located directly belowdewatering apparatus 252, first water filtration apparatus 256, andsecond filtration apparatus 258. It should be understood that FIGS. 1and 5, arranged as indicated in FIG. 6, comprise an overall view of thesystem of the present invention.

Slag dewatering apparatus 252 comprises an oscillating separating tank260, and associated equipment including a flume 262 fed by slurrypipeline 188, a water discharge conduit 264, and a framework 268 forsupporting the tank 260 above ground level 270.

Flume 262 is a wide, sloping trough having a bottom member 274 and likeside members 276. Flume 262 is supported at a slight angle to thehorizontal, e.g., between about 5 and 10 in any convenient manner, suchas by a framework omitted from the drawing for clearer illustration ofthe other parts. .A series of vertical rods 278, project upwardly fromflume bottom member 274 and serve as velocity killers to reduce thevelocity of the slurry entering settling tank 260.

As mentioned, settling tank 260 is of the continuously oscillating type,such as is frequently employed in sand and gravel quarries, and iscommercially available from several sources. The settling tank iscomprised of a. large metal hopper 280, generally in the form of aninverted pyramid. Hopper 280 is constructed in any suitable fashion, asof a plurality of properly shaped welded plates. Hopper 280 is freelysupported by a pair of knife-edged bearings 282, as illustrated, or inany other suitable fashion on framework 268 at a point somewhatdownstream (i.e., toward the right in FIG. 7) of its center of gravity.A baffle plate 284 extends completely across hopper 280 and is secured,as by welding, to the opposite sidewalls of the hopper, preferablydirectly above knife-edge bearings 282.

As illustrated, hopper 280 tapers downwardly, the taper being defined bya pair of sloping plate members 286 and 208, forming the upstream anddownstream sides, respectively, of the hopper, and by additional sideplates 290 connected by a short horizontal portion 292 at the truncatedapex of the inverted pyramid.

Slag discharge from hopper 280 is provided by.means of a drainageopening 294 at the bottom of backplate 286. Opening 294 is normallyclosed by means of a drainage gate 296, movably supported as by means ofa bellcrank 298 attached through a sloping connecting rod 300 to acounterweighting mechanism generally denoted at 302.

Counterweighting mechanism 302 includes a horizontally elongatedbalancing arm 304 terminating in a relatively high mass member 306 whichserves as the counterweight. Balance arm 304 is pivotally secured in anysuitable fashion at 308 to the upper portion of hopper backmember 286,and rests on a suitable support such as knife-edge bearing 310 mountedon framework 268. Connecting rod 300 is pivotally secured to balancingarm 304 to operate drainage gate 296 when hop 280 oscillates on bearings282 as now described.

In operation, the granulated slag-water slurry pumped through pipeline188 by pump 170, is discharged from flue 262 into hopper 280. The slurrystrikes baffle 284 and is deflected back to fill the hopper.

As the slurry level builds up, the heavy slag particles settle out ofthe water to the bottom of the hopper while the water flows under baffleplate 284. When it reaches a sufficient level, the water flows out overthe downstream end of hopper 280, e.g., over a transverse spillway to acollection trough 312. The water is then conducted into dischargepipeline 264 which is connected to first filter 256.

When the weight of the slag collecting at the bottom of hopper 280becomes sufficient, the unbalance about knifeedged bearings 282 willcause the hopper to tilt slightly in the counterclockwise direction.Since counterclockwise rotation of balance arm 304 is prevented bysupport bearing 310, bellcrank 298 and attached drainage gate 296 remainfixed, while pivoting of the rotating hopper causes drainage opening 294to be exposed. This results in discharge of the relatively drygranulated slag particles on to the stockpiling conveyor 254 asamplified below.

When a sufficient quantity of slag has been discharged, hopper 334becomes unbalanced in the opposite direction, causing it to swing back(in the clockwise direction) toward its initial position. Counterweight306 maintains balance arm 304 in a horizontal position, causing drainagegate 296 to be closed and preventing further slag discharge. Since onlya portion of the slag collected at the bottom of hopper 280 isdischarged at a given time, there is always maintained a relatively deepslag bed in the hopper above which the water is collected. This preventsdischarge of water through drainage gate 296. At the same time, thecontinuous oscillating motion of hopper 280 imparts an oscillatorymovement to the slurry which promotes separation of the slag and waterand results in a more rapid settling out of the slag particles.

As previously mentioned, settling tank 260 is a commercially availabledevice frequently used for dewatering sand or like material. Onesuitable device of this type is the so-called Telsmith Sand Tank,manufactured by the aforementioned Smith Engineering Works. SuchTelsmith Sand Tanks are capable of handling 1,700 or more gallons ofslurry per minute and of extracting about 135 tons of granulated slagper hour, (i.e., approximately 2.25 tons per minute). Since maximum loadoperation of the granulators may produce slurry flow in excess of theseamounts, a buffer tank, including a recirculating pump and a controlledslurry takeoff as described above, may be connected between slurrypipeline 188 and flume 262. Preferably, however, a series of sand tanks260, operating in tandem, should be employed with sufficient overallcapacity to handle the maximum expected slurry flow. As will beappreciated, suitable connecting troughs and runners to distribute theslurry uniformly among all of the settling tanks employed, are connectedat the output of pipeline 188 and feed a flume 262, associated with eachsettling tank. I

As previously mentioned, the substantially dry granulated slagdischarged through drainage opening 294 at the bottom of hopper 280,falls onto stockpiling conveyor 26S and is thereby transported to anearby stockpile 218. Conveyor 265 comprises a continuous motor-drivenbelt 316 of heavy duty design, and a framework 320 of generallytriangular configuration pivotally secured at 322 under hopper 280.

Reversible drive means 324 including a drive wheel 326 and a drive motor328, is mounted at the apex of triangular framework 320 to propelconveyor 254 in a wide are about pivot point 322. This permitsdistribution of the dried granulated slag output of hopper 280 over arelatively wide area.

Conveyor 254 is preferably a radial stacking conveyor such asmanufactured by the Barber-Greene Company of Aurora, 1",, or any othercommercially available equivalent. Since such apparatus is readilyavailable, further description of its construction is omitted in theinterest of brevity.

Water flowing into settling tank collection trough 312 passes throughdischarge conduit 264 to the input of first filtration apparatus 256.Filter 256 comprises a large settling basin 330 having straight sides332 and a sloping bottom 334. Basin 330 is of large size, e.g., having adiameter of as much as l feet or more and is preferably formed of castconcrete or the like directly supported on or below ground 336 or in anyother desired fashion.

A large metal framework 338 extends diametrically across basin 330.Framework 338 terminates in a pair of downwardly depending legs 340resting on opposite sides of the peripheral rim 342 of the basin.

Supported at the center of framework 338 is a motor housing 344, withinwhich is secured a suitable electric motor for rotating a vertical driveshaft 346 supported also by framework 338 and extending downward to thelowermost point 348 on tank bottom 334.

Attached in any suitable manner near the lower end of drive shaft 346,are a pair of rake arms 350 and 352 extending outwardly along slopingbottom 334 to vertical sides 332. Rake arms 350 and 352 are slightlyspaced above and are disposed substantially parallel to sloping tankbottom 334, as illustrated in FIG. 5. Secured to the undersides of rakearms 350 and 352 are a series of scraper plates 354 which serve toloosen and remove the solid material and sludge accumulated on tankbottom 334 as described below.

The lowermost point 348 of tank bottom 334 is provided with a drainopening 356 communicating with a sump 358 for receiving the residualsolid material extracted from the water entering filter 256 in the formof a sludge or thick suspension of very fine slag particles and dust. Acooperating drainage pump 360 of any suitable type is adapted toevacuate the material collecting in sump 358 through a suitabledrainpipe 362. An overflow pipe 364 extending through an aperture 366,near the top of tank sidewall 332, serves as a discharge conduit for therelatively clean water from which the slag particles have beenextracted.

In operation, the water output of settling tank 260 enters filter 256through feed pipe 264, e.g., near the center of basin 330. Since thelatter is quite large, a substantial quantity of water accumulates in arelatively calm state, whereby the heavy solid particles settle slowlyto the bottom. The clarified water passes out through drain 364 and issufficiently clean for direct discharge into nearby sewers or rivers.

As previously mentioned, the solid content of the water settles to thebottom of the basin and forms a relatively thick sludge or a watersuspension of extremely fine solid particles. Due to the slopingconfiguration, a portion of the sludge falls to the lowermost point 348at the bottom of the tank, and is discharged through drain opening 356into sump 358. The remainder tends to accumulate on the tank bottom.

To prevent such accumulation, rake arms 350 and 352 are slowly rotatedby drive shaft 346 whereby the attached scraper blades 354 continuouslyscour tank bottom 334 to remove the settling sludge' The drive motor fordrive shaft 346 preferably turns at an extremely slow speed so that thelinear velocity of the outer portions of rake arms 350 and 352 is keptquite small. This minimizes disturbance of the settling process sincerapid motion of the rake arms would tend to keep the solid material insuspension. The sludge removed from tank bottom 334 by scraper blades354 flows down along the sloping tank bottom through drain 356 into sump358 and is evacuated as explained above through drainpipe 362.

The outlet end of drain pipe 362 is connected to second filtrationapparatus 258, which operates to remove a substantial portion of thewater remaining in the sludge output of first filter 256. Filter 248 ispreferably a rotating drum vacuum filter such as the Horizontal RotaryFilter manufactured by the aforementioned Dorr-Oliver Company, or anycommercially available equivalent. Filter 258 includes a housing 336having a shallow well 368 at the bottom for receiving the sludgedischarged by drainpipe 362. A hollow cylindrical drum 370 formed of anextremely fine wire mesh is mounted in housing 366 and is adapted forrotation about a central axis 372 by suitable means such as an electricmotor (not shown). Drum 370 is so positioned that the lowermost portion374 is submerged within the sludge accumulating in well 368. The wirescreen forming drum 370 is such that a quantity of the sludge adheres tothe drum as it passes through well 368, whereby a thick coating or cake376 of the sludge material is carried upwardly as the drum rotates.

F ixedly mounted within drum 370 is a vacuum water extraction chamber378, extending the entire length of the drum (into the plane of FIG. 5),parallel to rotation axis 372. Chamber 375 may be in the form of anelongated cylindrical sector having a pair of closed radial sides 380and end plates 381, and a perforated arcuate outer face 382 conformingin curvature to the inner surface of drum 370. The interior of chamber378 is connected to a suitable suction pump (not shown), for creating apartial vacuum below the upper portion of drum 370. Thus, as the cake376 adheringto drum 370 passes over the extraction chamber open face382, the water is drawn down through the cake and into the chamber fromwhich it is removed in any suitable manner, such as drainpipe 384. Sincethe relatively thick cake 376 on drum 370 serves as a filtration bed,the extracted water is of sufficiently high purity to permit directdisposal into a nearby river or sewer.

The dried solid material remains on the outer surface of drum 370 afterpassing across the open face 382 of water exwherein said intermediatevessel is a tundish with an aperture located and dimensioned so thatmolten slag is poured into said granulator at a rate withinpredetermined limits.

8. An apparatus as defined in claim 7 wherein said tundish includesmeans for establishing a substantially fixed maximum rate of slag flowto said granulator independent of the rate of slag flow to said tundish.

9. Slag handling apparatus as defined in claim 8 wherein; said means forestablishing a maximum rate of slag flow to the granulator comprises ameans to permit overflow of slag from said tundish when the quantity ofmolten slag therein exceeds a predetermined head with respect to saidtundish aperture through which molten slag is poured into thegranulator.

10. Slag handling apparatus as defined in claim 1 wherein said slagfeeding means comprises: a slag ladle; crane means for transporting saidslag ladle from the location of a metal refining furnace to the locationof said granulator; an auxiliary tundish; said crane means includingmeans for controllably pouring the contents of said ladle into saidtundish; said tundish including a pouring opening in the wall thereof,overflow means in the wall of said vessel at a predetermined level abovesaid pouring opening to limit maximum head of molten slag in the tundishabove said pouring opening; and pouring means for pouring molten slagdischarged through said tundish pouring opening into said granulatorreceptacle to intercept said jetstreams of water.

11. Slag handling apparatus as defined in claim 1 wherein saiddewatering means comprises: tank means connected to said hydraulictransport means for receiving said slag-water slurry, said tank meansincluding means to promote separation of the water and the granulatedslag particles; and means for conducting the residual water and residualgranulated slag particles from said tank means after separation.

12. Slag handling apparatus as defined in claim 11 wherein said tankmeans includes means for classifying said granulated slag particlesaccording to size while separating said particles from said water.

13. Slag handling apparatus as defined in claim 11 wherein said means topromote separation includes means for imparting oscillation to theslurry accumulated therein to cause settlement of slag particles to thebottom of said tank means, means for discharging a portion of saidsettled slag, and means at the top of said tank means for removing theresidual water and for conducting the same to the filter means.

14. Slag handling apparatus as defined in claim 1 wherein said filtermeans comprises first means for settling remaining solid material out ofsaid residual water in the form of a water suspension of fine slagparticles, means for extracting said filtered water and conducting sameto a disposal location, means for conducting said suspension from saidsettling means, and means for extracting a substantial portion of thewater in said suspension.

15. Slag handling apparatus as defined in claim 1 wherein said hydraulictransport means comprises discharge conduit means, and pump meansconnected to said conduit means for propelling said slag through saidconduit in the form of a granulated slag/water slurry.

16. Apparatus as defined in claim 15 wherein said slag-slurry transfermeans includes an auxiliary tank for receiving granulated slag from saidgranulator receptacle, and means connecting said pump means to saidauxiliary tank for removal of said slag from said tank andtransportation through said conduit means.

17. A method of handling molten steel slag from a steelmaking furnacecomprising: pouring molten steel slag into a receptacle; injecting atleast one jetstream of water into said receptacle to intercept saidmolten steel slag to granulate said slag into particles; said waterjetstream being injected at a rate of at least 400 g.p.m. per ton ofmolten steel slag input per minute with a water jet velocity rangingfrom at least about 25 f.p.s. for a slag input rate of up to 2 tons perminute to at least about 55-6l f.p.s. for a slag input rate of up toabout 8 tons per minute; maintaining the water accumulating in saidreceptacle at a level below said water jetstream at all times whilemolten steel slag is being poured into said receptacle so that themolten steel slag intercepts said jetstream above the water accumulatedin said receptacle; removing resultant granulated slag particles fromsaid receptacle while granulation of the molten steel slag is inprogress; transporting said granulated slag away from said granulator inthe form of a water-slag slurry, separating the granulated slag from thewater in said slurry to permit storage and disposal of said slag inrelatively dry form; and filtering the residual water from the slurry toreduce the solids content thereof below a predetermined level.

18. A method of handling molten steel slag as set forth in claim 17wherein said step of filtering comprises extracting remaining solidmaterial from said water in the form of a water suspension of fine slagand dust, and extracting the fines from the water of said suspension.

19. A method of handling molten steel slag comprising: pouring moltensteel slag into a receptacle; injecting at least one jetstream of waterinto said receptacle so as to intercept said molten steel slag togranulate the molten slag into particles; the water stream beinginjected with a jet velocity of at least about 25.0 f.p.s. and at leastabout 400 g.p.m. for a molten slag input rate of up to about 2 tons perminute, the water stream being injected with a jet velocity of at leastabout 30 to 36.5 f.p.s. and at least about 500 to 600' g.p.m. for amolten slag input rate of 2 to about 4 tons per minute, the water streambeing injected with a jet velocity of at least about 36.5 to 55 f.p.s.and at least about 1,200 to 1,800 g.p.m. for a slag input rate of 4 toabout 7 tons per minute, and the water stream being injected with a jetvelocity of at least about 55 to 61 f.p.s. and at least about 1,800 to2,000 g.p.m. for a slag input rate to 7-8 tons per minute; maintainingwater accumulating in said receptacle at a level below said jetstreamwhile said molten steel slag is being poured into the receptacle so thatthe molten steel slag intercepts said jetstream above water accumulatedin the receptacle; removing resultant granulated slag particles fromsaid receptacle while the granulation of the molten steel slag is inprogress; transporting said granulated slag away from said granulator inthe form of a water-slag slurry; separating the granulated slag fromsaid slurry to permit storage and disposal thereof in relatively dryform, recovering the resultant water, and filtering said recovered waterto reduce the solids content thereof to below a predetermined level.

20. The method as set forth in claim 19 wherein said step oftransporting said slag away from said granulator comprises the steps ofpumping said slag through a conduit in the form of said water-slagslurry.

21. A method of handling molten steel slag as recited in claim 20wherein said water-slag slurry is impelled through said conduit at avelocity of at least about 17 f.p.s. from where it is removed from thegranulating receptacle to where the slag is extracted from the slurry.

22. An apparatus for handling molten slag comprising: a slag granulatorincluding a receptacle; means for feeding molten slag into thereceptacle; nozzle means for injecting one or more jetstreams of waterinto the receptacle to intercept the molten slag, means for controllingthe velocity and quantity of the injected water so as to granulate saidslag into particles; means for maintaining water accumulating in thereceptacle at a level below the jetstreams while said molten slagintercepts the jetstreams above the level of the water accumulated inthe receptacle; means for removing the granulated slag from thegranulator and transporting it away from the granulator for disposal;said means for feeding molten slag to the granulator comprising a slagcontainer for receiving molten slag from a furnace, and means fortransferring said molten slag from said slag container into saidgranulator receptacle at a controlled rate within predetermined limitsin relation to the velocity and quantity of said waterjetstream orstreams.

23. Slag handling apparatus as defined in claim 22 wherein saidtransferring means includes means for tilting said slag container toempty said container at a controlled rate.

traction chamber 378. This solid material is removed from the drumbefore the latter reenters well 368 by means of a scraper plate 386extending inwardly from housing 366 to engage the surface of drum 370.Scraper plate 386 and the sides of housing 366 form a collection bin 388for temporarily receiving the cake 376 as it is scraped off drum 370.Bin 388 is connected to a suitable discharge spout 390 which emptiesonto a discharge pile 392 for the extracted solid material. The smallquantity of water remaining in the fine material discharged throughspout 390 either evaporates or filters down through the stockpiledmaterial 392 and is ultimately dissipated in the earth.

If desired, the initial slag-water separating operation may be carriedout in conjunction with a size classification of the solid material. Ifthis is desired, apparatus such as indicated at 390 in FIG. 7 may besubstituted for the oscillating separating tank 352 shown in FIG. 5.Classifying tank 394 is preferably one of several known devices such asthe Telsmith Dewatering and Classifying Tank, manufactured by theaforementioned Smith Engineering Works. Since the latter and severalfunctionally equivalent devices are commercially available, detaileddescription is not deemed necessary. Briefly, however, classifying tank394 is comprised of an elongated settling tank portion 396 having aseries of longitudinally spaced discharge valves 398a-398k. Amulticompartmented classifying bin 400 is mounted below valves 398a 398kfor receiving the solid material discharge as described below. Theentire structure is supported on a suitable framework 402 above aplurality of stockpiles 404, 406, 408, etc., or suitable storage binsfor the granulated slag material.

In operation, the granulated slag-water slurry is transported, aspreviously explained, through pipeline 188 by dredge pump 170 (see FIG.ll). As the slurry discharges from pipeline 188 into tank 396, thepressure and velocity constraints which maintain the granulated slagparticles in suspension, are removed. As the water flows along and fillsthe tank, the slag particles tend to settle out of the stream. Theheaviest material settles at the upstream end of the tank, i.e., in thevicinity of valves 398a, 398b, etc., while the lighter material tends totravel further and to be deposited in the vicinity of valves 398g, or398k. Since particles of intermediate size tend to settle at variouspoints along the length of the tank, a multigrade classification of thegranulated slag particles is achieved.

In the Telsmith Classifying Tank referred to above, means are providedto open each of valves 398a-39811 automatically when the accumulation ofslag particles around a particular valve exceeds a preestablishedquantity. This may be accomplished, for example, by a series of paddles3l0a-3l0h rotated by suitable motors 3l2a-312h. As the paddles rotate,increasing weight of deposited slag particles causes increasingresistance to rotation and reduction of speed. When the reduction inspeed of a given paddle indicates the accumulation of the predeterminedweight of particles, the associated valve 398a-398h is opened, e.g.,pneumatically, and a portion of the accumulated slag material isdischarged into classifying bin 400. Only a small portion of theaccumulated slag is discharged leaving a relatively deep solid bed aboveeach valve. This minimizes the passage of water through the valve withthe granulated slag material.

The discharge from one or more of valves 398a 398h may be collected, ifdesired, and combined to form a single particle-size classification.Thus, as illustrated in FIG. 7, classifying bin 400 is provided withonly three discharge spouts 414, 416, and 148, feeding coarse, medium,and fine stockpiles 304, 306, and 308, respectively. Of course, it willbe appreciated that any number of stockpiles may be utilized; a separatedischarge bin may be provided for each of valves 398a398h if desired.

The partially clarified water is discharged by overflowing the top ofsettling tank 396 into a peripheral gutter 420, which in turn emptiesinto a discharge pipe 422. Preferably, first and second filtrationapparatus such as 256 and 258, described above in connection with FIG.5, are utilized in order to provide effective filtration of the waterprior to its discharge into nearby rivers and streams.

Thus, there has been described above, an improved system using the steelslag granulation apparatus of my parent applications in conjunction withadditional equipment for effective transportation of the granulated slagas a water-slag slurry, and for water extraction and filtration. Itshould be understood, however, that numerous variations of the abovedescribed system will be apparent to one skilled in the art in light ofthe disclosure.

For example, structural modifications or modifications of thearrangements specifically described may be made without departure fromthe basic concepts taught herein. Again, it will be appreciated thatspecifically described commercially available apparatus may be modifiedor replaced by functionally equivalent apparatus without departure fromthe scope of the invention.

Thus, the invention may be embodied in other specific forms withoutdeparting from the spirit or essential characteristics thereof. Thepresent embodiment is therefore considered in all respects illustrative,and not restrictive, the scope of the invention being indicated by theappended claims rather than by the foregoing description and all changeswhich come within the meaning and range of equivalency of the claims aretherefore intended to be embraced therein.

What is claimed is:

1. An apparatus for handling and treating molten slag comprising: a slaggranulator including a receptacle; means for feeding molten slag intothe receptacle; nozzle means for injecting one or more jetstreams ofwater into the receptacle to intercept the molten slag and to granulatesaid slag into particles; means for maintaining water accumulating inthe receptacle at a level below the jetstreams while said molten slagintercepts the jetstreams above the level of the water accumulated inthe receptacle; hydraulic transport means for transporting thegranulated slag from the granulator in the form of a water-slag slurry;dewatering means for separating granulated slag from the water in saidslurry; and filter means coupled to said dewatering means for receivingthe residual slurry to reduce the solids content thereof to below apredetermined level.

2. Slag handling apparatus as defined in claim 1 further comprising:means for collecting steam produced by contact of the slag with water insaid granulator, without substantial emission thereof from thegranulator; means for transporting the collected steam from thegranulator; and means for venting said steam to atmosphere at anappropriate discharge location.

3. Slag handling apparatus as defined in claim 1 wherein said nozzlemeans comprises at least one generally horizontally disposed nozzle withan aperture of relatively small vertical dimensions and substantiallygreater horizontal dimension; and means connecting said nozzle means toa supply of water including means for preventing particles larger thansaid smaller vertical nozzle dimension from reaching said nozzle.

4. Slag handling apparatus as defined in claim 1 wherein said nozzlemeans comprises a first section for injecting at least one generallyhorizontal water jetstream component into said granulator receptacle,second and third sections for injecting second and third generallyvertical jetstream components into said granulator receptacle, saidfirst, second, and third nozzle components being so positioned relativeto each other that the composite jetstream is of generally U-shapedconfiguration.

5. Slag handling apparatus as defined in claim 1 further comprisingmeans for pouring molten slag into the granulator at a predeterminedrate.

6. Slag handling apparatus as defined in claim 1 wherein said means forfeeding molten slag into the granulator comprises: means fortransporting molten slag from a metal refining furnace; intermediatevessel means for receiving said molten slag and discharging the slag tosaid granulator receptacle at a rate within predetermined limits.

7. Slag handling apparatus as defined in claim 6 wherein; said transportmeans includes a slag pot and means for tilting said pot to pour moltenslag into said intermediate vessel; and

24 Slag handling apparatus as defined in claim 23 wherein saidtransferring means includes an auxiliary vessel for receiving slagpoured from said container, aperture means in the wall of said vessel,and overflow means in the wall of said vessel at a predetermined levelabove said aperture to limit the maximum head of molten slag above saidaperture.

25. Slag handling apparatus as defined in claim 22 further includingmeans for conveying said slag container from a furnace location to thegranulator and means for emptying said container at a controlled rate.

26. Slag handling apparatus as defined in claim 22 wherein said meansfor removing said slag from said granulator and t i t

2. Slag handling apparatus as defined in claim 1 further comprising:means for collecting steam produced by contact of the slag with water insaid granulator, without substantial emission thereof from thegranulator; means for transporting the collected steam from thegranulator; and means for venting said steam to atmosphere at anappropriate discharge location.
 3. Slag handling apparatus as defined inclaim 1 wherein said nozzle means comprises at least one generallyhorizontally disposed nozzle with an aperture of relatively smallvertical dimensions and substantially greater horizontal dimension; andmeans connecting said nozzle means to a supply of water including meansfor preventing particles larger than said smaller vertical nozzledimension from reaching said nozzle.
 4. Slag handling apparatus asdefined in claim 1 wherein said nozzle means comprises a first sectionfor injecting at least one generally horizontal water jetstreamcomponent into said granulator receptacle, second and third sections forinjecting second and third generally vertical jetstream components intosaid granulator receptacle, said first, second, and third nozzlecomponents being so positioned relative to each other that the compositejetstream is of generally U-shaped configuration.
 5. Slag handlingapparatus as defined in claim 1 further comprising means for pouringmolten slag into the granulator at a predetermined rate.
 6. Slaghandling apparatus as defined in claim 1 wherein said means for feedingmolten slag into the granulator comprises: means for transporting moltenslag from a metal refining furnace; intermediate vessel means forreceiving said molten slag and discharging the slag to said granulatorreceptacle at a rate within predetermined limits.
 7. Slag handlingapparatus as defined in claim 6 wherein; said transport means includes aslag pot and means for tilting said pot to pour molten slag into saidintermediate vessel; and wherein said intermediate vessel is a tundishwith an aperture located and dimensioned so that molten slag is pouredinto said granulator at a rate within predetermined limits.
 8. AnapparaTus as defined in claim 7 wherein said tundish includes means forestablishing a substantially fixed maximum rate of slag flow to saidgranulator independent of the rate of slag flow to said tundish.
 9. Slaghandling apparatus as defined in claim 8 wherein; said means forestablishing a maximum rate of slag flow to the granulator comprises ameans to permit overflow of slag from said tundish when the quantity ofmolten slag therein exceeds a predetermined head with respect to saidtundish aperture through which molten slag is poured into thegranulator.
 10. Slag handling apparatus as defined in claim 1 whereinsaid slag feeding means comprises: a slag ladle; crane means fortransporting said slag ladle from the location of a metal refiningfurnace to the location of said granulator; an auxiliary tundish; saidcrane means including means for controllably pouring the contents ofsaid ladle into said tundish; said tundish including a pouring openingin the wall thereof, overflow means in the wall of said vessel at apredetermined level above said pouring opening to limit maximum head ofmolten slag in the tundish above said pouring opening; and pouring meansfor pouring molten slag discharged through said tundish pouring openinginto said granulator receptacle to intercept said jetstreams of water.11. Slag handling apparatus as defined in claim 1 wherein saiddewatering means comprises: tank means connected to said hydraulictransport means for receiving said slag-water slurry, said tank meansincluding means to promote separation of the water and the granulatedslag particles; and means for conducting the residual water and residualgranulated slag particles from said tank means after separation. 12.Slag handling apparatus as defined in claim 11 wherein said tank meansincludes means for classifying said granulated slag particles accordingto size while separating said particles from said water.
 13. Slaghandling apparatus as defined in claim 11 wherein said means to promoteseparation includes means for imparting oscillation to the slurryaccumulated therein to cause settlement of slag particles to the bottomof said tank means, means for discharging a portion of said settledslag, and means at the top of said tank means for removing the residualwater and for conducting the same to the filter means.
 14. Slag handlingapparatus as defined in claim 1 wherein said filter means comprisesfirst means for settling remaining solid material out of said residualwater in the form of a water suspension of fine slag particles, meansfor extracting said filtered water and conducting same to a disposallocation, means for conducting said suspension from said settling means,and means for extracting a substantial portion of the water in saidsuspension.
 15. Slag handling apparatus as defined in claim 1 whereinsaid hydraulic transport means comprises discharge conduit means, andpump means connected to said conduit means for propelling said slagthrough said conduit in the form of a granulated slag/water slurry. 16.Apparatus as defined in claim 15 wherein said slag-slurry transfer meansincludes an auxiliary tank for receiving granulated slag from saidgranulator receptacle, and means connecting said pump means to saidauxiliary tank for removal of said slag from said tank andtransportation through said conduit means.
 17. A method of handlingmolten steel slag from a steelmaking furnace comprising: pouring moltensteel slag into a receptacle; injecting at least one jetstream of waterinto said receptacle to intercept said molten steel slag to granulatesaid slag into particles; said water jetstream being injected at a rateof at least 400 g.p.m. per ton of molten steel slag input per minutewith a water jet velocity ranging from at least about 25 f.p.s. for aslag input rate of up to 2 tons per minute to at least about 55-61f.p.s. for a slag input rate of up to about 8 tons per minute;maintaining the water accumulatiNg in said receptacle at a level belowsaid water jetstream at all times while molten steel slag is beingpoured into said receptacle so that the molten steel slag interceptssaid jetstream above the water accumulated in said receptacle; removingresultant granulated slag particles from said receptacle whilegranulation of the molten steel slag is in progress; transporting saidgranulated slag away from said granulator in the form of a water-slagslurry, separating the granulated slag from the water in said slurry topermit storage and disposal of said slag in relatively dry form; andfiltering the residual water from the slurry to reduce the solidscontent thereof below a predetermined level.
 18. A method of handlingmolten steel slag as set forth in claim 17 wherein said step offiltering comprises extracting remaining solid material from said waterin the form of a water suspension of fine slag and dust, and extractingthe fines from the water of said suspension.
 19. A method of handlingmolten steel slag comprising: pouring molten steel slag into areceptacle; injecting at least one jetstream of water into saidreceptacle so as to intercept said molten steel slag to granulate themolten slag into particles; the water stream being injected with a jetvelocity of at least about 25.0 f.p.s. and at least about 400 g.p.m. fora molten slag input rate of up to about 2 tons per minute, the waterstream being injected with a jet velocity of at least about 30 to 36.5f.p.s. and at least about 500 to 600 g.p.m. for a molten slag input rateof 2 to about 4 tons per minute, the water stream being injected with ajet velocity of at least about 36.5 to 55 f.p.s. and at least about1,200 to 1,800 g.p.m. for a slag input rate of 4 to about 7 tons perminute, and the water stream being injected with a jet velocity of atleast about 55 to 61 f.p.s. and at least about 1,800 to 2,000 g.p.m. fora slag input rate to 7-8 tons per minute; maintaining water accumulatingin said receptacle at a level below said jetstream while said moltensteel slag is being poured into the receptacle so that the molten steelslag intercepts said jetstream above water accumulated in thereceptacle; removing resultant granulated slag particles from saidreceptacle while the granulation of the molten steel slag is inprogress; transporting said granulated slag away from said granulator inthe form of a water-slag slurry; separating the granulated slag fromsaid slurry to permit storage and disposal thereof in relatively dryform, recovering the resultant water, and filtering said recovered waterto reduce the solids content thereof to below a predetermined level. 20.The method as set forth in claim 19 wherein said step of transportingsaid slag away from said granulator comprises the steps of pumping saidslag through a conduit in the form of said water-slag slurry.
 21. Amethod of handling molten steel slag as recited in claim 20 wherein saidwater-slag slurry is impelled through said conduit at a velocity of atleast about 17 f.p.s. from where it is removed from the granulatingreceptacle to where the slag is extracted from the slurry.
 22. Anapparatus for handling molten slag comprising: a slag granulatorincluding a receptacle; means for feeding molten slag into thereceptacle; nozzle means for injecting one or more jetstreams of waterinto the receptacle to intercept the molten slag, means for controllingthe velocity and quantity of the injected water so as to granulate saidslag into particles; means for maintaining water accumulating in thereceptacle at a level below the jetstreams while said molten slagintercepts the jetstreams above the level of the water accumulated inthe receptacle; means for removing the granulated slag from thegranulator and transporting it away from the granulator for disposal;said means for feeding molten slag to the granulator comprising a slagcontainer for receiving molten slag from a furnace, and means fortransferring said molten slag from said slag container into saidgranulator receptacle at a controlled rate within predetermined limitsin relation to the velocity and quantity of said water jetstream orstreams.
 23. Slag handling apparatus as defined in claim 22 wherein saidtransferring means includes means for tilting said slag container toempty said container at a controlled rate.
 24. Slag handling apparatusas defined in claim 23 wherein said transferring means includes anauxiliary vessel for receiving slag poured from said container, aperturemeans in the wall of said vessel, and overflow means in the wall of saidvessel at a predetermined level above said aperture to limit the maximumhead of molten slag above said aperture.
 25. Slag handling apparatus asdefined in claim 22 further including means for conveying said slagcontainer from a furnace location to the granulator and means foremptying said container at a controlled rate.
 26. Slag handlingapparatus as defined in claim 22 wherein said means for removing saidslag from said granulator and transporting it away from said granulatorcomprises hydraulic transfer means including conduit means, and pumpmeans connected to said conduit means for propelling said slag throughsaid conduit in the form of a granulated slag/water slurry. 27.Apparatus as defined in claim 26 wherein said slag-slurry transfer meansincludes an auxiliary tank for receiving granulated slag from saidgranulator receptacle, and means connecting said pump means to saidauxiliary tank for removal of said slag from said tank andtransportation through said conduit means.